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Get the current free disk space in PostgreSQL

PostgreSQL获取磁盘空间

Here has a simple way to get free disk space without any extended language, just define a function using pgsql.

CREATE OR REPLACE FUNCTION sys_df() RETURNS SETOF text[]
LANGUAGE plpgsql $$
BEGIN
    CREATE TEMP TABLE IF NOT EXISTS tmp_sys_df (content text) ON COMMIT DROP;
    COPY tmp_sys_df FROM PROGRAM 'df | tail -n +2';
    RETURN QUERY SELECT regexp_split_to_array(content, '\s+') FROM tmp_sys_df;
END;
$$;

Usage:

select * from sys_df();
                      sys_df                               
-------------------------------------------------------------------
 {overlay,15148428,6660248,7695656,46%,/}
 {overlay,15148428,6660248,7695656,46%,/}
 {tmpfs,65536,0,65536,0%,/dev}
 {tmpfs,768284,0,768284,0%,/sys/fs/cgroup}
 {/dev/sda2,15148428,6660248,7695656,46%,/etc/resolv.conf}
 {/dev/sda2,15148428,6660248,7695656,46%,/etc/hostname}
 {/dev/sda2,15148428,6660248,7695656,46%,/etc/hosts}
 {shm,65536,8,65528,0%,/dev/shm}
 {/dev/sda2,15148428,6660248,7695656,46%,/var/lib/postgresql/data}
 {tmpfs,65536,0,65536,0%,/proc/kcore}
 {tmpfs,65536,0,65536,0%,/proc/timer_list}
 {tmpfs,65536,0,65536,0%,/proc/sched_debug}
 {tmpfs,768284,0,768284,0%,/sys/firmware}
(13 rows)

Using df $PGDATA | tail -n +2 instead of df | tail -n +2 while you saving all data in same path on disk. In this case, the function only return one row disk usage for $PGDATA path.

NOTE FOR SECURITY

PROGRAM can run any command by shell, it like two-edged sword. it is best to use a fixed command string, or at least avoid passing any user input in it. See detail on document.

PROGRAM可以运行任意的命令，所以最好是用固定字符串命令，尽量避免通过参数传入。

How to get the free disk space in PostgreSQL (PostgreSQL获取磁盘空间)

标签：timer   spl   exp   function   simple   saving   str   time   group   

原文地址：https://www.cnblogs.com/eshizhan/p/11444001.html